FORT DODGE, IOWA, JAN. 13 -- Vice President Bush said for the first time today that in the presence of others he voiced reservations about the secret Iran arms sales that went beyond his previously stated concerns about the role of Israel in the covert operation.

Bush said, "I also had the concerns that I have when any covert action is undertaken -- how will it be interpreted if the cover is blown? Will lives be lost? Will our credibility be damaged? Unfortunately, my reservations turned out to be well-founded."

The vice president's comments came in written responses delivered today to 17 questions posed by Washington Post columnist Mary McGrory in her column Tuesday. Pressed by his rivals for a fuller explanation of his role in the gravest foreign policy crisis of the Reagan presidency, Bush has been taking a more aggressive tack in responding to questions about it.

Bush's new reservations were not mentioned in the reports of the Tower commission or of the congressional Iran-contra committees. Under questioning by reporters for months, he has not mentioned these reservations. Up to now, the only mention of how to deal with the problems of public exposure of the arms sale, for example, came in testimony of then-White House chief of staff Donald T. Regan. He told the Tower commission that none of President Reagan's advisers "teed up for him of what the downside risk would be here . . . . No one attempted to do this. I don't believe the State Department in its presentation arguing against this really brought out the sensitivity of this."

In his written comments, Bush did not say when he voiced reservations or who heard them. He has repeatedly said in recent campaign appearances that he stood "solidly" with the president and would not reveal what advice he gave Reagan privately. Bush again vowed today not to disclose his advice to Reagan but said the additional reservations were made in a "setting with others present."

Reagan was asked last March 19 whether Bush objected to the Iran arms sales. "No," he said. White House spokesman Marlin Fitzwater later said Bush had expressed reservations to the president but "always supported the policy and the decisions."

The vice president said today for the first time that records show he "probably" participated in the critical Jan. 7, 1986, meeting with Reagan and other senior Cabinet officials who raised objections to the arms sales, including Secretary of State George P. Shultz and then-Secretary of Defense Caspar W. Weinberger.

However, Bush said, "I do not recall any strenuous objection. Had there been any strenuous objection, I am sure I would have remembered it." Bush said he did not ask Shultz or Weinberger for their views.

"Nor do I recall their soliciting my views, again in large part because the usual NSC {National Security Council} process for sharing views had not been invoked," Bush said.

The vice president noted that he was absent from several key meetings in 1985 on the Iran arms sales, including one on Dec. 7 in the White House residence at which "objections were apparently forcefully stated" by others. Bush was on his way to the Army-Navy football game.

Bush renewed his complaint that the decision-making process in the Iran arms sales was "flawed." He said "there never was a formal NSC {National Security Council} meeting on the Iran initiative where all the risks and benefits could be aired by all the participants at the same time." He also said, "If we had had the benefit of the formal NSC process, I think the president and I would both have understood the breakdown in implementing our policy."

The congressional report described the Jan. 7, 1986, meeting as a full NSC meeting, but the vice president said today it was an "ad hoc" meeting. An informed source with direct access to official records said there were two meetings that day -- one in the White House Situation Room and a smaller one in the Oval Office with Reagan -- and that Bush apparently attended both.

Last week, The Post reported that Bush had watched the secret Iran arms deals unfold, in part through his attendance at morning national security briefings with the president. Bush responded by saying the meetings were not detailed, but only brief updates on the hostages' plight.

But today the vice president said it was at one such meeting that he learned that Reagan's former national security adviser Robert C. McFarlane was planning to visit Tehran. Bush said, "I've never stated anything to the contrary." A computer message made public last year shows that Bush wanted McFarlane's mission delayed until after his own trip to the Persian Gulf region. Bush also attended McFarlane's briefing of the president on his return.

Bush was asked how he reconciled his stated concern for the Americans held hostage in Lebanon with his claim that the weapons shipments were not part of a trade to free them.

"I have stated over and over again that the original proposal was not presented as an arms for hostages swap," Bush said. He added that "all during the discussions" he was "terribly concerned about getting the hostages out and about the torture of the man that I knew to be a CIA station chief," a reference to William Buckley, the CIA station chief in Beirut who was tortured and murdered.

Bush denied that the arms sales "subverted" the report on fighting terrorism that a task force he chaired issued during the same period as the weapons shipments. The report said U.S. policy was not to make concessions to terrorists. "I was not subverting it because I do not believe in trading arms for hostages," Bush said.

He did not elaborate. Bush said this week that he knew at the time of the arms sales that Iran was listed by the State Department as one of the nations supporting terrorism.

Staff writer Walter Pincus contributed to this report.